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Help: CLICK Master Slave

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  • Help: CLICK Master Slave

    I need some advice. Project: I need a CLICK to watch the water level of a tank. When that level is to low or to high it sends via 485 a remote CLICK and turns on ans output for an alarm. Basically remote I/O.
    I have been able to get the CLICKS to communicate with a very simple program. My hang up how do I address / send that x001 is on so remote y001 should be on.

  • #2
    Reserve three 'C' bits in the 'remote'. Send to one of them (let's say C001) the status of X001. The other two will be used for handshaking. Let the master read the status of the remote's C002. The master then inverts that status and sends it back to the remote's C003.

    Now we talk about the remote's program. As long as communication is ok (we'll see this in a moment) then send the status of C001 out to Y001.
    Now to check communication. Copy the status of C003 to C002. Also use the NO of C003 to enable a timer, use the NC of C003 to enable another timer. timer preset of each should be at least twice as long as the time to send a message. It can be longer to prevent nuisance trips. If either timer ever reaches 'done' then no messages have been received for a while. Take what ever default action you wish (what is safer the output staying on, turning off or just remaining in the last state? You decide.). Why does this work? C002 and C003 will be toggling back and forth with each message. If it stops then communication has stopped.
    thePLCguy

    Bernie

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    • #3
      Sounds somewhat mad to run the same number of conductors you'd need to operate the contact on the alarm device then add another plc and a couple of rungs of code just to again operate the contact on the alarm device.

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      • #4
        I'm imagining that he will add more functions after getting this single one going. It's good to start simple. But if it we're just for this one thing it is overkill
        thePLCguy

        Bernie

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        • #5
          This makes so much more sense! Thank you. I make the program idea simple for the sake of not having to type it all out. The situation is these two clicks will be around a 1/2 mile apart, so wire is out of the question. I am using two 485 transceivers, that are pass through so it works great. I have a simple program showing they are communicating. My hold up was figuring out how to control the slave. After getting this going I will do the rest of my logic.
          Last edited by D.Williams; 12-31-2019, 02:51 AM.

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